package day07;

import jdk.management.resource.internal.inst.FileOutputStreamRMHooks;

import java.nio.channels.NonReadableChannelException;
import java.util.Random;

//生成4位的Verifiyondae(_大写字母，小写字母，数字
public class VerificationCode {
    public static void main(String[] args) {
        String code =generateVeriCode(4);
        System.out.println("验证码："+code);
    }
    public static String generateVeriCode(int len){
        String code="";
        char[] chs={'a','b','c','d','e','f','g','h','i','j','k','l','m','n',
                    'o','p','q','r','s','t','u','v','w','x','y','z','A','B',
                    'C','D','E','F','G','H','I','J','K','L','M','N','O','P',
                    'Q','R','S','T','U','V','W','X','Y','Z','0','1','2','3',
                    '4','5','6','7','8','9'};
        Random rand = new Random();
        for (int i=1;i<=len;i++){
            /*int index=(int) (Math.random()*chs.length);
            code += chs[index];*/
            int index =rand.nextInt(chs.length);
            code += chs[index];
        }
        return code;



/*
        char[] chs={'a','b','c','d','e','f','g','h','i','j','k','l','m','n',
                'o','p','q','r','s','t','u','v','w','x','y','z','A','B',
                'C','D','E','F','G','H','I','J','K','L','M','N','O','P',
                'Q','R','S','T','U','V','W','X','Y','Z','0','1','2','3',
                '4','5','6','7','8','9'};*/
    }
}